US President Joe Biden was among the first to confirm he would be at the event, which will be attended by up to 2,000 people.
“I don’t know what the details are yet, but I’m going,” Biden told reporters on Friday.
Brazil’s Jair Bolsonaro and South Korea’s Yun Suk-yeol are among the presidents who attended the queen’s final abdication after a series of ceremonial events.
Newly elected UK Prime Minister Liz Truss will also mourn the monarch next week.
The leaders of most Commonwealth countries are expected to attend, with New Zealand Prime Minister Jacinda Ardern and Australian Prime Minister Anthony Albanese making the nearly 24-hour trip.
“I would prioritize, of course, along with the Governor-General, doing our part on behalf of New Zealand and conveying the condolences of our entire nation,” Ardern told TVNZ on Friday. “I expect there will be a number of leaders who want to pay homage and tribute to the Queen,” he added.
Japan’s Emperor Naruhito and Empress Masako will travel to London for the queen’s funeral, an unusual move that demonstrates the close relationship between the Japanese and British royal families.
Japan’s Asahi Shimbun news agency reported, citing Imperial Household Agency officials, that a Japanese emperor had attended the funeral of a foreign head of state or member of the royal family only on one previous occasion, when then-Emperor Akihito attended the funeral of Belgian King Baudouin in 1993.
Members of foreign royal families will also sit in the pews on Monday.
Spain’s King Felipe VI and his wife Queen Letizia are among the European royals to attend.
The King and Queen of the Netherlands, along with the country’s former Queen Beatrix, who abdicated in 2013, will also be at the church, the Dutch royal house said.
Jordan’s King Abdullah II, who remembered the queen as an “iconic leader” and a “beacon of wisdom and principled leadership”, will also attend her funeral.
However, not all world leaders have been invited.
Syria, Venezuela and Afghanistan are three of the countries that have not been asked to send a representative, according to British news agency PA Media.
Representatives from North Korea and Nicaragua have been invited “only at ambassadorial level,” the PA added.
The leaders of Russia, Belarus and Myanmar will also be absent.
Although Russian President Vladimir Putin tweeted his congratulations on King Charles III’s ascension to the throne, diplomatic relations between the United Kingdom and Russia have collapsed following Russia’s invasion of Ukraine, a senior government source told CNN of the United Kingdom on Tuesday.
Belarusian President Alexander Lukashenko is a close ally of President Putin.
Myanmar will not be invited, following a coup in the country last year.
After the funeral, Queen Elizabeth II will be buried in St George’s Chapel at Windsor Castle, where her parents, her sister Princess Margaret and her husband Prince Philip are also buried.
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CNN’s Alex Hardie contributed to this report.